|Battery O'Rorke was built to mount four 15-pounder, 3 inch guns, serial numbered 90, 91, 92 and 94, on Model 1903 pedestal mounts. The mounts were built by the Watertown Arsenal and were serial numbered 68 through 71. It was not armed for many years, at least not until 1909. The battery was nevertheless named by War Department General Order 194 on December 27, 1904 in honor of Colonel Patrick Henry O'Rorke. Colonel O'Rorke, at native of Ireland and a graduate of the U.S. Military Academy at West Point, was killed at the age of 27 at the Battle of Gettysburg during the Civil War in July 1863.